Kt/V was used to quantify haemodialysis adequacy and was calculated using a second generation single-pool Daugirdas formula (Kt/V = -ln(R-0.03) + [(4-3.5 x R) x (UF/W)], where R = post-dialysis BUN/pre-dialysis BUN, UF = net ultrafiltration, W = weight, K= dialyzer clearance of urea, t= dialysis time, and V= patient's total body water.